Approaching 40, I can't think of any major, interesting ones of late in my professional career, but in my late teens I was working my first job at a race/repair shop (after a few semesters of high-school auto shop).
Once there were three of us dropping in a new motor (into I forget what... But it was a big, fully dressed v8). After a first attempt, we had to pull the motor back. As we did so, one of the two adjustable legs on the engine hoist slipped out of its sleeve sending the whole motor to the ground from maybe 4 feet up. Cracked the block and a few other bits. The worst part was the shop owner was shady and told us to patch it in some ridiculous way. I was too young and dumb to speak up about it, sadly.
